some students slowly add solution y to solution...

Q1. Some students slowly add solution Y to solution X.

The graph shows what happens to the pH of the solution in the beaker as they do this.

(a) Choose words from this list to complete the sentences below.

acidic alkaline neutral

At point A on the graph the solution in the beaker is ...............................................

At point B on the graph the solution in the beaker is ...............................................

At point C on the graph the solution in the beaker is ............................................... (2)

(b) Describe, as fully as you can, what happens to the pH of the mixture as solution Y is slowly added.

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(Total 7 marks)

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Q2. Powdered magnesium oxide was added in 0.1 g amounts to 25 cm3 of dilute hydrochloric acid and the mixture stirred. The powder soon reacted and disappeared, but after about 1.0 g had been added it took some time for all the solid to react. When a total of 1.1 g of powder had been added, some of the magnesium oxide remained at the bottom of the flask.

(a) On the following axes draw a sketch graph to show how the pH of the liquid is likely to change during the experiment described above. Start the graph with the pH of the acid before any magnesium oxide is added.

(3)

(b) A second experiment was done using magnesium oxide from the same bottle with

25 cm3 of the same hydrochloric acid.

There is no catalyst for this reaction. Suggest two ways in which the rate of this reaction could have been speeded up.

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(c) (i) What is the symbol for the oxide ion?

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(ii) Complete the ionic equation for the reaction between hydrogen ions and oxide ions.

................................. + ................................. → H2O

(2)

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(iii) The experiment was repeated, but 25 cm3 of dilute sulphuric acid was used instead of hydrochloric acid.

The concentration of the sulphuric acid was the same as the hydrochloric acid (0.1 M).

Why was twice as much magnesium oxide needed to neutralise the sulphuric acid completely?

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(Total 9 marks)

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Q3. Chemical tests can be used to identify compounds.

The table shows the results of some tests carried out on three solutions, A, B and C.

Use the information in the table to identify solutions A, B and C.

Give the name of:

(a) solution A; ................................................................................................................... (2)

(b) solution B; ................................................................................................................... (2)

(c) the metal ion in solution C. ......................................................................................... (1)

(Total 5 marks)

Solution Flame Test Hydrochloric

acid is added

Sodium hydroxide solution is added

Silver nitrate solution is added

A Yellow

Carbon dioxide gas produced

B Brick-red White precipitate insoluble in

excess sodium

hydroxide solution

White precipitate

C

Dark green precipitate

Q4. Tennis players sometimes use smelling salts to help revive them.

The active chemical in smelling salts is ammonium carbonate, (NH4)

2CO

3.

Describe how smelling salts can be tested to show that they contain ammonium ions and carbonate ions. Give the results of the tests.

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(a) Test and result for ammonium ions

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(b) Test and result for carbonate ions

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(Total 4 marks)

Q5. Chlorine and bromine are important Group 7 elements.

(a) Explain why chlorine is added to drinking water.

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(b) Describe what you would see when bromine water is added to an unsaturated organic compound.

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(c) Bromine can be extracted from seawater. The dissolved bromide ions are reacted with chlorine. Bromine and chloride ions are formed.

(i) Complete and balance the equation below, which represents the reaction between chlorine and bromide ions.

Cl2 + 2Br– → ......................... + .........................

(1)

(ii) Describe what you see when chlorine is added to a solution containing bromide ions.

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(d) In terms of electronic structure:

(i) state why bromine and chlorine are both in Group 7

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(ii) explain why bromine is less reactive than chlorine.

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(e) What is the result of adding acidified silver nitrate solution to a solution containing:

(i) chloride ions

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(ii) bromide ions?

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(Total 10 marks)

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Q6. This label has been taken from a packet of My Baby Food.

One of the minerals in My Baby Food is calcium carbonate, CaCO3.

MY BABY FOOD

Infant milk Pure and natural

Closest to mothers’ breast milk Contains traces of essential minerals

500 g

(a) Chemical tests are used to identify elements and compounds.

(i) A flame test can be used to identify calcium ions. What colour do calcium ions give in a flame test?

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(ii) When a flame test was carried out on My Baby Food, the presence of calcium ions was not seen. A yellow flame was produced. Name the ion which gives a yellow flame test.

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(iii) Suggest one advantage of using an instrumental method to detect the elements present in My Baby Food.

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(iv) Name an instrumental method for detecting elements.

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(b) Read the information in the box below and then answer the question.

Many people do not agree with Mrs Right’s ideas.

Suggest why.

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(Total 7 marks)

Calcium carbonate occurs naturally as marble and limestone. They are important building materials and are often used for gravestones.

Calcium carbonate is also an essential mineral for good health and is present in many baby foods in small amounts.

My Baby Food is recommended as being the closest to a mother’s own breast milk. It is given free to mothers in the developing world – without it their babies might die of malnutrition.

Responsible Mothers Are Us (RMAU) is a United Kingdom pressure group. They want to ban chemicals in baby foods. The group was founded by Mrs I. M. Right who has made a career in ‘goodness’ and is paid from donations given to RMAU by members of the public.

When interviewed, she said: “Calcium carbonate is a chemical and so it is a pollutant. My Baby Food must be banned to prevent the mass medication of babies. I don’t feed my baby the stuff of gravestones.”

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Q7. The label is from a packet of Low Sodium Salt.

(a) A student tested some Low Sodium Salt to show that it contains carbonate ions and chloride ions.

(i) Describe and give the result of a test for carbonate ions.

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(ii) A student identified chloride ions using acidified silver nitrate solution.

State what you would see when acidified silver nitrate solution is added to a solution of Low Sodium Salt.

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(iii) Flame tests can be used to identify potassium ions and sodium ions.

Suggest why it is difficult to identify both of these ions in Low Sodium Salt using a flame test.

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(b) Read the following information and then answer the questions.

Salt – friend or foe?

Sodium chloride (salt) is an essential mineral for our health. It is used to flavour and preserve foods. Too much sodium in our diet may increase the risk of high blood pressure and heart disease. Heart disease is the biggest cause of death in the United Kingdom. Some people claim that excess sodium is a poison that can cause cancer, while others say that more evidence is needed.

Many processed foods contain salt, so it is easy to exceed the recommended daily upper limit of about 5 g of salt per person. A ‘healthier’ amount should be about 3 g. In the United Kingdom many people consume over 10 g of salt each day.

One way to reduce sodium in our diet is to use Low Sodium Salt. This has two thirds of the sodium chloride replaced by potassium chloride.

A national newspaper asked readers for their views on two options.

Option 1: Ban the use of sodium chloride in foods.

Option 2: Reduce the amount of sodium chloride in all foods to a ‘healthier’ level.

(i) Suggest why Option 1 was rejected.

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(ii) Suggest two advantages and one disadvantage of Option 2.

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(Total 8 marks)

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Q8. Drain Buster is used to clear and degrease drains. Sodium hydroxide is the main chemical substance in Drain Buster.

(a) A student planned an experiment to find the concentration of the sodium hydroxide solution in Drain Buster.

The teacher had to dilute the Drain Buster before the student could use it.

Explain why.

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(b) In this question you will get marks on using good English, organising information clearly and using specialist terms where appropriate.

The student wanted to find the volume of hydrochloric acid that reacts with a known volume of diluted Drain Buster.

Describe how the student could do this by titration. In your description you should include: • the names of pieces of apparatus used • the names of the substances used • a risk assessment

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(Total 8 marks)

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Q9. Alums are salts. They have been used since ancient times in dyeing and medicine and still have many uses today.

Three alums are shown in the table:

(a) These alums contain sulfate ions (SO4

2-).

Describe and give the result of a chemical test to show this.

Test ................................................................................................................

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Result .............................................................................................................

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Name Ions present

Ammonium alum NH4

+ Al3+ SO

4

2-

Potassium alum K+ Al3+ SO

4

2-

Sodium alum Na+ Al3+ SO

4

2-

(b) These alums contain aluminium ions (Al3+).

Describe how sodium hydroxide solution can be used to show this.

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(c) Aluminium ions do not give a colour in flame tests. However, flame tests can be used to distinguish between these three alums.

Explain how these three alums could be identified from the results of flame tests.

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(Total 6 marks)

Q10. Go Grease is a drain and oven cleaner.

The active ingredient in Go Grease is the alkali sodium hydroxide (NaOH).

(a) Name or give the formula of the ion that makes solutions alkaline.

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(b) Sodium hydroxide is a strong alkali.

In terms of ionisation, what is meant by the word strong?

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(c) You are given solutions of sodium hydroxide and ammonia of the same concentration.

Describe and give the results of a test to show that sodium hydroxide is a stronger alkali than ammonia solution.

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(Total 4 marks)

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Q11. Read the information about protecting the bottoms of ships.

(a) Use the information to answer the following questions.

(i) Suggest why copper replaced lead.

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A Copper-bottomed Investment

From the 16th to the 19th century, the bottoms of many wooden ships were protected from marine organisms by being covered with sheets of metal.

At first lead was used on the bottoms of ships, then copper was used until 1832 when Muntz Metal replaced it. Muntz Metal is an alloy of two transition metals, copper and zinc.

Table of data

Lead Copper Muntz Metal

Cost (£/kg) £1.20 £3.20 £2.30

Melting point (°C) 327 1083 904

Stops sea worms attacking wood Yes Yes Yes

Stops barnacles and seaweed sticking to the bottom of the ship

No Yes Yes

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(ii) Suggest why Muntz Metal replaced copper.

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(b) A sample of Muntz Metal contains a very small amount of iron as an impurity.

(i) Name an instrumental method of analysis that could be used to detect iron.

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(ii) Suggest why an instrumental method would detect the iron in this sample of Muntz Metal but a chemical method is not likely to be successful.

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(c) Today, ships are made from steel. Steels are alloys of iron, a transition metal.

Give two properties of transition metals that make them suitable for making ships.

Property 1 ......................................................................................................

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Property 2 ......................................................................................................

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(Total 6 marks)

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Q12. Cheshunt mixture is a powder containing copper sulfate, CuSO4, and ammonium

carbonate, (NH4)

2CO

3

(a) A student tested the Cheshunt mixture.

(i) Hydrochloric acid was added. A gas was produced that turned limewater milky.

Complete the sentence.

The gas was .................................................................... which shows

that .................................................. ions are in the mixture. (2)

(ii) Sodium hydroxide solution was added. A gas was produced that indicates that ammonium ions are in the mixture.


The gas was .................................................................... which turns

damp red ...................................................................................... blue. (2)

(b) Cheshunt mixture is dissolved in water before it is used. When the student dissolved the Cheshunt mixture in water it formed a blue solution.

(i) Suggest how the student knew that copper ions are in this solution.

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(ii) The student tested the Cheshunt solution and the result of the test indicated that sulfate ions are in the solution.


The student added a solution of ............................... in the presence of

dilute hydrochloric acid and a ............................... precipitate was produced. (2)

(Total 7 marks)

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Q13. In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate.

A student used the equipment shown to do a titration.

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Describe how the student should use this equipment to find the volume of sodium hydroxide solution that reacts with a known volume of acid. Include any measurements the student should make.

Do not describe how to do any calculations.

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some students slowly add solution y to solution...

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